In recent years, tracks are provided on a disk in a higher density to increase the storage capacity in the field of disk storage apparatuses a representative example of which is a hard disk drive (HDD in some instances). On any disk having tracks arranged in a high density, the more times data has been written in one track, the magnetic recording in either peripheral track will be degraded, due to the influence the recording magnetic field imposes during the data writing. The degradation of the magnetic recording may result in read errors.
For addressing the influence imposed on either peripheral track (adjacent track interference [ATI]), a method (anti-ATI measures) has been proposed, in which a track refresh process is performed. In the track refresh process, the times data has been written each track on a disk is counted and the data recorded in the track is refreshed in accordance with the number of times data has been written in the track.
The track refresh process is a process designed to update the data recorded in any track if data has been recorded in the track more times than a reference value (threshold value). More specifically, the data thus far recorded is read from the track and then is written again in the track (thereby refreshing the track with the same data).
The track refresh process is performed while the HDD is idling, in order to reduce the load on the ordinary read/write process. If the recording magnetic field influences either peripheral track very much, however, the ordinary read/write process must be interrupted and the track refresh process must then be immediately performed, even while the HDD keeps operating.